In recent years, polymer (macro-molecule) materials have been increasingly utilized in a variety of fields. Accordingly, characteristics of their surfaces and interfaces have become important as well as their polymer characteristics as a matrix in each field. For example, it has been expected that using a fluorine-based compound having low surface energy as a surface modifying agent improves characteristics related to surface and interface control such as water repellency and oil repellency, antifoulingness, nonadhesiveness, peeling properties, mold releasability, slidability, wear resistance, anti-reflection characteristics, and chemical resistance, and various technologies have been developed.
Various displays such as LCDs (liquid crystal displays), PDPs (plasma displays), and touch panels have, on their surfaces, various plastic films that contain an anti-scratch hard coating layer. The hard coating layer is easily tainted with fingerprints and smudges adhering thereto, and the adhering fingerprints and smudges cannot be easily removed. This makes images on the display appear seriously blurred and adversely affects appearance of the display. In particular, a touch panel comes into direct contact with fingers on its surface and is therefore strongly desired to have properties, in particular, to prevent fingerprints from easily adhering to the surface and to easily remove the adhering fingerprints.
Regarding films that have such a hard coating layer, for the purpose of making the surface of the hard coating layer flat (level or smooth) and applying anti-smudge properties to the surface, a technique has been developed in which a hard coating layer is formed by adding a silicon compound and a fluorine compound to a hard coating layer-forming coating solution that contains an active energy ray-curable composition. These compounds have anti-fingerprint properties such as protection against fingerprint adhesion and fingerprint wiping-off properties as well as functions to improve smoothness and anti-smudge properties against permanent marker ink or the like.
For example, a hard coating layer-forming composition is described that includes a fluorine-containing highly branched polymer and a perfluoropolyether compound or a silicone compound so as to obtain excellent surface properties such as anti-fingerprint properties and excellent resistance to solvent wiping-off properties (Patent Document 1).
By the way, the surface of a display with a capacitive touch panel function, which is typified by the surface of a smartphone, is generally glass from functionality and design standpoints. The glass surface has anti-scratch properties, anti-fingerprint properties, and anti-smudge properties. To the glass surface, however, the active energy ray-curable composition as described above does not have adhesion because the active energy ray-curable composition shrinks to a great extent on curing and does not form a chemical bond with the glass surface. Because of this, the glass surface is provided with a film that includes a hard coating layer having anti-fingerprint properties and anti-smudge properties so as to apply these functions to the glass surface.
As a method for improving adhesion of a hard coating layer that includes an active energy ray-curable composition to the glass surface, a technique is described in which a reaction product of a hydroxy group-containing multifunctional acrylate and an alkoxysilane compound is used as a component to promote adhesion of a multifunctional acrylate to the glass (Patent Document 2).